1. Field of the Invention
The present invention relates to a system and method of injection blow molding and injection molding device, and particularly to a system and method of injection blow molding in which preforms are injection molded before temperature regulating, and then blow molded into containers.
2. Description of the Prior Art
One of the injection blow molding systems for molding containers is described in Japanese Patent Publication No. 3-45692, for example.
The injection blow molding system described in this Japanese Patent Publication No. 3-45692 is shown in FIG. 15 of the accompany drawings and comprises an injection molding station 2, a first temperature regulating station 4, a second temperature regulating station 6, a blow molding station 8 and a removing station 10, all of which are arranged in a line.
The injection molding station 2 simultaneously injection molds two rows of four preforms 12 arranged in a direction perpendicular to a preform carrying direction shown by an arrow in this figure. The pitch P1 between two rows of the injection molded preforms 12 (which will be referred to "the injection molding pitch P1") is then changed to a larger pitch P2 for blow molding in the blow molding station 8(which will be referred to "the blow molding pitch P2"). The preforms 12 are then carried through the first and second temperature regulating stations 4, 6, blow molding station 8 and removing station 10 while the blow molding pitch P2 is maintained.
In the injection molding station 2, the preforms 12 are injection molded and carried in their upright state.
Since the injection blow molding system of Japanese Patent Publication No. 3-45692 is designed to change the injection molding pitch P1 to the blow molding pitch P2 immediately after the preforms 12 have been injection molded, the preforms 12 will be carried with this larger pitch P2 from the injection molding station 2 through the first and second temperature regulating stations 4, 6 to the blow molding station 8. This causes a waste of space in the first and second temperature regulating stations 4, 6, resulting in increase of the entire system size and manufacturing cost.
When beverage containers or the like are to be molded by such a system, it is desired to maintain the molding room clean. When such a clean atmosphere is to be maintained in the larger area, the installation and maintenance costs will be increased. To avoid this, it is important to reduce the area of installation as small as possible.
Furthermore, such an injection blow molding system is designed to carry the upright preforms 12. When the preforms 12 are heated, the necks of the erected preforms 12 may be excessively heated to be undesirably deformed because the necks of the preforms 12 are topped and the heat moves upward. In this case, further, carrying members used to carry the preforms may also be adversely affected by the heat.
Since the preforms 12 are blow molded by the blow molding station 8 in their upright state, the necessary parts for blow molding the preforms 12 such as stretching rods and others must be placed above the preforms 12. This will increase the entire height of the system and raise a problem in the installation space and maintenance.